Numerical Analysis of Impact Induced Failure for MEMS Membranes during Guided Free Fall Tests

Impact effects on thin silicon MEMS membranes attached to dummy devices, as observed through guided free fall tests, are investigated through three-dimensional, finite element numerical simulations. Accounting for the different scales involved, a multiscale top-down approach is followed: fluid dynamics and solid mechanics macro-scale simulations are first carried out, to provide input histories for fluid (air) pressures and relative displacements for the thin silicon membrane anchors at the micro-scale. Then, a mechanical analysis is carried out for each membrane to judge whether possible failures arise in a given guided free fall test. It is found that in some cases possible failures actually depend from the combination of the fluid-induced and of the solid-induced input transferred to the MEMS membrane, and not from a single domain-induced loading condition.